O2 evolution and electron transfer activity of chloroplast in Gingko took on descending current in the process of senescence, but it had a maximum in September. 3.

• 3、在自然生长条件下雌、雄银杏叶绿体在衰老过程中，片层逐渐降解，膜结构逐渐解体，油脂颗粒增大增多，内部结构趋于简单，以至叶绿体瓦解，最终导致了银杏叶片光合速率的下降。